Wireless communications arrangements with location based services

ABSTRACT

In a wireless communications arrangement, a method is disclosed of providing location based services to at least one mobile terminal MT, the mobile terminal MT being adapted for roaming between a plurality of access points AP 1 -n and for wireless communication therebetween. The access points AP 1 -n are controlled by a network control means ( 10 ) and the method includes: a) the control means ( 10 ) activating location based services LBS only on receipt of a predetermined message sent thereto from the mobile terminal MT though an access point AP; and b) the control means ( 10 ) determining the location of the mobile terminal MT based on a network address of an access point AP through which said predetermined message was sent and directing said location based services LBS to said mobile terminal MT through said access point AP.

The present invention relates to wireless communications arrangementsand in particular to wireless communications arrangements in whichlocation based services are provided to a mobile terminal. The inventionalso relates to wireless communications units, methods and software usedin such arrangements.

Wireless LANs are becoming popular nowadays, not only in indoorenvironments but also in outdoor spaces. By means of wireless accesspoints, mobile terminals can use networking services similar to thoseavailable in a wired LAN.

When a mobile device roams from one access point to another, in somecases it is useful to deliver position-specific content to the user.Many interesting applications are based on location dependentinformation retrieval and a mobile user can access information that istightly coupled with its position, even if such information iscentralized at the server's side. For example, the content of a Web pagecould change according to the access point the user is connected to. TheWeb server, therefore, must be able to detect the mobile terminal'slocation and be able to change the content delivered according to it.

Once a mobile terminal reaches an access point, IP communication betweenmobile users and an associated server may be possible, along with thesubsequent desire for the provision of location based services (LBS).Context aware information delivering often requires mobile userlocalization; i.e. the server needs to customize services based onuser's context: examples are user or position-specific or related webpage contents.

In U.S. Pat. No. 6,101,387 a system is proposed for providing networkoriginated notification of location based services to mobile stations.In this proposal, however, it is necessary to provide means forrecording subscriber information and this takes the form of a visitinglocation register (VLR). This register includes a database containingtemporary identification and subscriber information about all knownmobile stations currently located in the area of coverage of anassociated mobile switching center (access point). The VLR may comprisea stand-alone unit or may be integrated into the mobile switchingcenter.

In U.S. 2001/0018349A1, a system is proposed for providinglocation-based services to a plurality of mobile terminals within anarea of coverage. The services offered are to be supplied in associationwith mobile terminal location and tracking. Mobile terminal location maybe determined from a variety of location determining means or fromsignals supplied from the mobile terminal itself. The user in thisproposal has to actively discover which services are available and thelocation server is constantly active for tracking mobile terminals.

This issue of mobile terminal localization can be addressed at theaccess points by installing short-range devices in charge of pushing asmall amount of location dependent information to the mobile user, as inthe “Cooltown” approach. “Cooltown” is a project by Hewlett Packard thatprovides architecture and various technologies to build and deploy LBS.In the “Cooltown” approach, a mobile user is made aware of its positionand appropriate tuned queries can then be addressed to the server 10.Mobile devices that approach a hotspot receive location information inthe form of a URL. The mobile device consequently sends a request to aserver, but in this case the location information is already known.While being a scalable mechanism, this architecture implies that eachaccess point must be configured with its location and must be able tosupply this information to the mobile device. This may prove difficultto configure and may require extra functionality in the access pointand/or mobile terminal. For example, a second shorter-range wirelessdata communications device could be needed in order for the mobileterminal to determine its own position. For further information inrelation to this option, the reader is referred to “Cooltown-people,places, things: web presence for the real world”, Time Kindberg et al.,HP Labs, Palo Alto, Calif. Sep. 3, 2001 and to the hyperlink:“http://cooltown.hp.com/dev/wpapers/webpres/WebPresence.asp”.

Other approaches exist to implement LBS. One of them is based on the newmobility protocols that are being developed by the Internet EngineeringTask Force (ETF). One of these protocols is Mobile IP (MIP), whichenables roaming devices to transparently connect to their home networkindependently of their point of attachment to the Internet. Locationinformation can also be handled by Mobile IP extensions. MIP is acomplex algorithm that is unlikely to become widespread in a short timeand requires the updating of several existing types of networkcomponents, including many mobile terminals.

Other approaches to LBS are emerging that are based on complexmiddleware architectures for the mobile terminals. The main point inthis case is the use of standardized communications protocols that workon top of the transport layer, in such a way that they can handlelocation information transparently to the user or to the applications.This approach may require several years to stabilize, until a commonapproach emerges from the huge amount of different existing technologies(CORBA, UPnP, Jini, SOAP, etc.).

It is a problem with many current arrangements which propose locationbased services that they require additional hardware and/or software inone or both of the mobile terminal and the access point and many alsorequire active participation of the user in the location based servicediscovery and/or ordering procedures.

It is an object of the present invention to provide improved wirelesscommunications arrangements and in particular to provide improvedwireless communications arrangements in which location based servicesare provided to a mobile terminal. It is also an object of the presentinvention to provide improved wireless communications units, methods andsoftware products used in such arrangements.

According to the present invention there is provided, in a wirelesscommunications arrangement, a method of providing location basedservices to at least one mobile terminal, said mobile terminal beingadapted for roaming between a plurality of access points and forwireless communication therebetween, said access points being controlledby a network control means and the method including:

-   -   a) said control means activating location based services only on        receipt of a predetermined message sent thereto from said mobile        terminal through a said access point; and    -   b) said control means determining the location of said mobile        terminal based on a network address of an access point through        which said predetermined message was sent and directing said        location based services to said mobile terminal through said        access point.

The method may include sending said predetermined message in the form ofa dedicated request, such as a HyperText Transfer Protocol (HTTP)request, and a said location based service comprising for example anInternet or intranet web page.

The method may include providing access to said control means of anaddress of said mobile terminal.

The method may include said control means tracing and/or retrieving apath connecting said control means to said mobile terminal, in order toidentify an address of the last router before said mobile terminal.

The method may include, in the event that said access points areconfigured as routers, determining the substantially instantaneouslocation of said mobile terminal substantially directly from the networkaddress of the currently connected access point.

The method may include, in the event that said access points areconfigured as bridges, determining the substantially instantaneouslocation of said mobile terminal through the last router to which thecurrently connected access point is connected.

The method may include determining a medium access control (MAC) addressof said mobile terminal on the basis of an Internet protocol (IP)address of said mobile terminal.

The method may include said control means determining from said accesspoints which of them holds in its bridging tables said medium accesscontrol (MAC) address of said mobile terminal, the substantiallyinstantaneous location of said mobile terminal being identified from thenetwork address of said access point.

The method may include, after determining the substantiallyinstantaneous location of said mobile terminal, generating a saidlocation based service such as a web page and sending said service tosaid mobile terminal.

The method may include determining the at least temporary location ofsaid mobile terminal solely on the basis of the network address of anaccess point to which said mobile terminal is at least temporarilyconnected.

According to the present invention, a mobile terminal's location neednot be tracked by the server. Instead, its position may be determined bythe server every time the mobile terminal requests a location-dependentWeb page. This saves network and computing resources on both server'sand mobile terminal's sides. Therefore, the method may include saidcontrol means determining the position of a said mobile terminalsubstantially every time said mobile terminal requests a location basedservice.

The method does not rely on any specific kind of wireless technology inthe hardware used for mobile terminals or access points, rather merelythat the wireless technology used should be compatible with a LANprotocol such as Ethernet™. Therefore, the method may includeconfiguring said access points and the or each said mobile terminal tooperate in accordance with a LAN compatible, e.g. Ethernet compatiblewireless technology. Two non-limiting examples of such technologycomprise the Bluetooth radio standard and/or the IEEE 802.11 radiostandard.

The present invention also provides a computer readable medium havingrecorded thereon a software product for providing location basedservices to at least one mobile terminal in a wireless communicationsarrangement, said mobile terminal being adapted for roaming between aplurality of access points and for wireless communication therebetween,said access points being controlled by a network control means and thesoftware product including code for:

-   -   a) said control means activating location based services only on        receipt of a predetermined message sent thereto from said mobile        terminal though a said access point; and    -   b) said control means determining the location of said mobile        terminal based on a network address of an access point through        which said predetermined message was sent and directing said        location based services to said mobile terminal through said        access point.

Said software product may be adapted for execution in said controlmeans, said control means preferably comprising a server accessible by asaid mobile terminal. The server may be a server of a wireless localarea network of which the mobile terminal and access points form a part,but this is not necessarily so. The server may for example be anyway ona wide arena network such as the Internet and merely needs to beaccessible to the mobile terminal.

The present invention also provides a wireless communicationsarrangement comprising a plurality of access points under the control ofa control means and at least one mobile terminal which is adapted toroam between said access points and for wireless communicationtherewith, said control means being adapted to provide to said mobileterminal one or more location based services, wherein said control meansis adapted to activate location based services only on receipt of apredetermined message sent thereto from said mobile terminal though asaid access point, to determine the location of said mobile terminalbased on a network address of an access point through which saidpredetermined message was sent and to direct said location basedservices to said mobile terminal through said access point.

The present invention also provides a wireless communications unitadapted to operate in accordance with the method of the invention andpreferably configured at least temporarily as at least one of an accesspoint and a mobile terminal of a wireless communications arrangement,such as one adapted to be compatible with a LAN (local area network)protocol such as Ethernet™. Non-limiting examples of such an arrangementmight comprise a wireless system adapted to operate according to theBluetooth or IEEE 802.11 standard.

The present invention also provides a control means adapted to operatein accordance with the method of the invention and/or for executing thesoftware product of the invention.

FIG. 1 is a block diagram of a communications arrangement according toan embodiment of the present invention;

FIG. 2 is a flow chart of a method used in the arrangement of FIG. 1;

FIG. 3 is a flow chart of a subroutine (A) of the method of FIG. 2; and

FIG. 4 is a flow chart of a subroutine (B) of the method of FIG. 1, thissubroutine being an alternative subroutine to that of FIG. 3.

The present invention will now be described with reference to certainembodiments and with reference to the above mentioned drawings. Suchdescription is by way of example only and the invention is not limitedthereto.

Networks that include access points and that are able to providewireless access to a wide area network such as the Internet or anintranet or extranet are available and an example of such aconfiguration can be found in some corporate networks, where theIEEE802.11 standard is being deployed and mobile terminals do not needto be equipped with special software to access an intranet or theInternet. This may be embodied in a communications system based on awireless radio communications system such as the Bluetooth™ radiostandard. An arrangement of this type is supported by the disclosure inU.S. patent application 2001/0010689A1, in which interoperability isproposed between an IEEE 802.11 device and a Bluetooth transceiver.

According to the present invention, it is possible to implement locationbased services (LBS) in a wireless local area network (WLAN) usingstandard network components (routers, switches and access points).General information relation to wireless LAN's is described in the book“Wireless LAN's” by Jim Geier, Macmillan Technical Publishing, 1999.With LBS is meant the capability of a mobile terminal to presentdifferent content to the user depending on its position in the network.

Referring for the moment in particular to FIG. 1, a wireless local areanetwork (WLAN) includes a series of access points AP_(1-n) which areillustrated configured as bridges and are connected to a control meansin the form of a server 10 through a network backbone 12 comprising aseries of routers 14 _(1-n). It will, however, be appreciated thataccess points AP_(1-n) may also be embodied as routers 14 _(1-n). Itshould also be noted that, while the server is described here as aserver 10 of a wireless local area network of which the mobile terminaland access points form a part, this is not essential. The server 10 mayfor example be anyway on a wide area network of which the Internet isonly one example and merely needs to be accessible to the or each mobileterminal MT.

The access points AP_(1-n) are adapted for wireless communication withone or more mobile terminals MT, which may roam between access pointsAP_(1-n) in the network and may form at least temporary connections withan access point in whose area of coverage they fall at leasttemporarily. In the exemplary preferred embodiment, the wireless localarea network WLAN comprises a wireless personal area network WPAN,having for example access points AP_(1-n) with a range of about 10 m.The access points AP_(1-n) and any mobile terminals roaming in the WPANmay in addition be configured in accordance with the Bluetooth protocol.

Each mobile terminal MT_(1-n) is connected to a single access pointAP_(1-n) and in FIG. 1 only one mobile terminal MT₁ is illustrated andis shown by way of example as connected to an exemplary access pointAP₃. The server 10 is equipped with a server-side processing engine (notillustrated separately), which can produce dynamic Web content dependingon the output of a program, an example of such a program beingimplemented using PHP. It is worthy to note here that PHP is a scriptinglanguage used for dynamic web pages. When a client requests a PHP basedpage, the server passes the page to the PHP interpreter. The PHPinterpreter then executes the scripts and returns the output in the formof a dynamically generated HTTP page to the server 10.

There are two possible cases: in case A, each access point AP_(1-n) isan Internet protocol (IP) router, while in case B each access pointAP_(1-n) is an Ethernet bridge. In case B, all access points AP_(1-n)are directly connected to the same Ethernet network and the server 10,which may or may not be connected to the same Ethernet network, is awareof the IP addresses of all access points AP_(1-n).

Once a mobile terminal MT₁ reaches an access point AP₃, IP communicationbetween mobile users MT and the server 10 is made possible. Contextaware information delivery requires mobile user localization; i.e. theserver 10 needs to know where the mobile terminal MT₁ is in the networkin order to send location based services LBS such as person orposition-specific or related web page contents. According to the presentinvention, the server 10 achieves this localization purely on the basisof the access points AP_(1-n) to which the or each mobile terminal MT₁is connected. The actual provision of customized page contents can beachieved using, for example, server-side executable routines such as CGIand PHP. CGI (Common Gateway Interface) is a method for generatingserver-side dynamic Web pages, and can be considered as an alternativeto PHP.

Unlike some previous approaches, e.g. “Cooltown”, mobile terminal MT₁location discovery is performed by the server 10 itself, eliminating theneed of a pushing mechanism. A mobile terminal MT₁ requests informationfrom the server 10 by sending a predetermined message and the server 10is capable of acquiring the mobile terminal's IP address using PHPfacilities. Then, the server 10 can trace the route that reaches themobile terminal MT₁ by means of existing network tools, to which end thereader is referred by way of example to “Mobile Networking throughMobile IP”, C. Perkins, e.g. at:

-   -   http://www.computer.org/internet/v2nl/perkins.htm.        The last hop in the route represents the access point AP₃ the        mobile terminal MT₁ is connected to. The server 10 can therefore        send to the mobile terminal MT₁ a page whose contents depend on        the access point AP₃ identity.

Two main cases are possible. In the first one, access points AP_(1-N)behave as so-called “Access Routers” and invocation of a “Traceroute”tool leads to access-point AP_(1-n) identification. Tracerouteinformation can be found for example through the Internet EngineeringTask Force (IETF) request for comments RFC_(—)1393, “Traceroute Using anIP Option”, Xylogics Inc. January 1993.

In the second, and a little more complicated main case, access pointsAP_(1-N) behave as “Bridges” and “Traceroute” could only point out thelast IP router on the path towards the mobile terminal MT₁. The last hopcan then be identified by means of other network tools that exploit theSimple Network Management Protocol (SNMP) protocol. Details of the SNMPprotocol can be found through the Internet Engineering Task Force (IETF)request for comments RFC_(—)1157, “A Simple Network ManagementProtocol”, J. Case et al. May 1990.

The exemplary method used in the preferred embodiment may be embodied asan executable software product adapted to be run in the server 10. Theprogram may be summarized as outlined below and with particularreference to the flow charts of FIGS. 2 to 4.

-   -   Initially, the mobile terminal MT₁ asks for a Web page by        sending a predetermined message, e.g. in the form of a hyper        text transfer protocol HTTP request, to a server, asking for a        PHP application to be executed. The message's route from the        mobile terminal MT to the server 10 goes through its currently        connected access point AP₃.    -   PHP application on the server 10 can access the IP address of        the mobile terminal MT₁ that generated the HTTP request.    -   The PHP program invokes a “Traceroute” command to retrieve the        path of the IP packet that contained the HTTP request, in order        to identify the IP address of the last router 14 ₁ before the        mobile terminal MT₁. Two cases are now possible, A and B, as        represented by the subroutines shown with respect to FIGS. 3 and        4 respectively.    -   (A) If the access points AP_(1-n) are configured as IP routers,        the IP address of the access point AP₃ identifies a good        estimate of the mobile terminal MT₁ location substantially        directly, at least to within an area of coverage of that access        point AP₃.    -   The corresponding location based service LBS, e.g. a web page,        is generated and sent to the mobile terminal MT₁ in the HTTP        response.    -   The routine then ends END.    -   (B) If access points AP_(1-n) are configured as bridges, then        the “Traceroute” command does not identify the access point AP₃,        but rather the last router R₁ to which the access points AP are        connected.    -   The PHP application on the server 10 issues a Simple Network        Management Protocol (SNMP) request to the router R₁ for        retrieving the Medium Access Control (MAC) address of the mobile        terminal MT₁ based on its IP address, this preferably being        achieved by looking at the router's ARP tables. Address        Resolution Protocol (ARP) is a standard protocol that allows the        retrieval of the physical MAC address from the IP address. A        router 14 _(1-n), in order to send a packet to a mobile terminal        MT, first of all retrieves its MAC address by means of ARP, then        it is able to send the message. Every time a new IP address is        encountered, the IP address and the correspondent MAC address        are stored in the so-called “ARP table”, so MAC addresses for IP        addresses already in the ARP table are immediately known.    -   The PHP application then issues SNMP requests to each of the        access points AP connected to the router R to discover which of        them has the mobile terminal MT MAC address in its bridging        tables.    -   The access point AP that has the mobile terminal MT MAC address        identifies the mobile terminal MT location.    -   The corresponding location based service LBS, e.g. a Web page,        is generated and sent to the mobile terminal MT in the HTTP        response.    -   The routine then ends END.

According to the present invention, a mobile terminal's location neednot be tracked by the server 10. Instead, its position may be determinedby the server 10 every time the mobile terminal MT requests alocation-dependent Web page. This saves network and computing resourceson both the server's and mobile terminal's sides, as the mobileterminal's location is only required when it requests context awareinformation.

The present invention is applicable whenever the web server 10 iscontrolled by the same entity that manages access points AP_(1-n).

Possible examples of non-limiting embodiments are:

-   -   a web portal for a department in a corporate intranet, which        presents location-dependent information to employees or        visitors, e.g. services available in conference rooms or in        offices (printers, projectors, maps for visitors etc.);    -   a web server in a public area, such as a shopping mall or in an        airport, that gives users location-dependent information on        products or services, based on the determination of mobile        terminal position from the current access point address; and    -   one or more servers in a city, which offer maps and other type        of information to users that connect wirelessly to public        hotspots.

Other embodiments are possible as well. Many Internet service providers(ISP) are offering wireless access to the Internet to end-users andcustomization of their portal based on the suggested technique would bepossible. This is not limited to traditional ISP, but also to otherssuch as those who offer WLAN Internet access to their customers in forexample restaurants.

The present invention therefore offers simplicity in implementation, asit allows a web server to locate a mobile terminal without the need forspecial features such as a positioning system, e.g. GPS or similar.Furthermore, no modification is necessary in the mobile terminal MT orin the access point AP and all that they require is the ability to useexisting Internet protocol IP and to support a web browser whichsupports the HTTP standard protocol as specified by IETF (InternetEngineering Task Force). In the case that access points are Ethernetbridges, it is necessary that their ARP tables can be browsed by aremote server, for example by means of the standard SNMP protocol.Current industry standard protocols may be used and only the web serverneeds to be configured, corresponding to a centralized architecture. Inthe case of a high number of terminals, the server may also be easilydistributed, as happens in the most common Web services. It should alsobe noted that the present invention is preferably embodied in a wirelesspersonal area network WPAN, as the access points in such networks tendto have a range in the region of 10 m. This short range may provide moreaccurate localization of the mobile terminal than using access pointsused in some wireless local area networks WLAN, which may have ranges of10 m. To this end, a personal area network PAN configured in accordancewith the Bluetooth protocol is a good example of an arrangement in whichthe present invention may prove useful.

While the present invention has been particularly shown and describedwith respect to a preferred embodiment, it will be understood by thoseskilled in the art that changes in form and detail may be made withoutdeparting from the scope and spirit of the invention.

1. In a wireless communications arrangement, a method of providinglocation based services to at least one mobile terminal, said mobileterminal being adapted for roaming between a plurality of access pointsand for wireless communication therebetween, said access points beingcontrolled by a network control means and the method including: a) saidcontrol means activating location based services only on receipt of apredetermined message sent thereto from said mobile terminal through asaid access point; and b) said control means determining the location ofsaid mobile terminal based on a network address of an access pointthrough which said predetermined message was sent and directing saidlocation based services to said mobile terminal through said accesspoint.
 2. A method according to claim 1, including sending saidpredetermined message in the form of a dedicated request, such as aHyperText Transfer Protocol (HTTP) request, and a said location basedservice comprising for example an Internet or intranet web page.
 3. Amethod according to claim 1 or claim 2, including providing access tosaid control means of an address of said mobile terminal.
 4. A methodaccording to any preceding claim, including said control means tracingand/or retrieving a path connecting said control means to said mobileterminal, in order to identify an address of a last router before saidmobile terminal.
 5. A method according to claim 4 including, in theevent that said access points are configured as routers, determining thesubstantially instantaneous location of said mobile terminalsubstantially directly from the network address of the currentlyconnected access point.
 6. A method according to claim 4 including, inthe event that said access points are configured as bridges, determiningthe substantially instantaneous location of said mobile terminal throughthe last router to which the currently connected access point isconnected.
 7. A method according to claim 6, including determining amedium access control (MAC) address of said mobile terminal on the basisof an Internet protocol (IP) address of said mobile terminal.
 8. Amethod according to claim 9, including said control means determiningfrom said access points which of them holds in its bridging tables saidmedium access control (MAC) address of said mobile terminal, thesubstantially instantaneous location of said mobile terminal beingidentified from the network address of said access point.
 9. A methodaccording to any one of claims 5 to 8 including, after determining thesubstantially instantaneous location of said mobile terminal, generatinga said location based service such as a web page and sending saidservice to said mobile terminal.
 10. A method according to any precedingclaim, including determining the at least temporary location of saidmobile terminal solely on the basis of the network address of an accesspoint to which said mobile terminal is at least temporarily connected.11. A method according to any preceding claim, including said controlmeans determining the position of a said mobile terminal substantiallyevery time said mobile terminal requests a location based service.
 12. Amethod according to any preceding claim, including configuring saidaccess points and the or each said mobile terminal to operate inaccordance with a local area network compatible wireless technology. 13.A computer readable medium having recorded thereon a software productfor providing location based services to at least one mobile terminal ina wireless communications arrangement, said mobile terminal beingadapted for roaming between a plurality of access points and forwireless communication therebetween, said access points being controlledby a network control means and the software product including code for:a) said control means activating location based services only on receiptof a predetermined message sent thereto from said mobile terminal thougha said access point; and b) said control means determining the locationof said mobile terminal based on a network address of an access pointthrough which said predetermined message was sent and directing saidlocation based services to said mobile terminal through said accesspoint.
 14. A software product according to claim 13, adapted forexecution in said control means, said control means preferablycomprising a server accessible by a said mobile terminal.
 15. A wirelesscommunications arrangement comprising a plurality of access points underthe control of a control means and at least one mobile terminal which isadapted to roam between said access points and for wirelesscommunication therewith, said control means being adapted to provide tosaid mobile terminal one or more location based services, wherein saidcontrol means is adapted to activate location based services only onreceipt of a predetermined message sent thereto from said mobileterminal though a said access point, to determine the location of saidmobile terminal based on a network address of an access point throughwhich said predetermined message was sent and to direct said locationbased services to said mobile terminal through said access point.
 16. Awireless communications unit adapted to operate in accordance with themethod of any one of claims 1 to 12 and preferably configured at leasttemporarily as at least one of an access point and a mobile terminal ofa wireless communications arrangement.
 17. A control means adapted tooperate in accordance with the method of any one of claims 1 to 12and/or for executing the software product of claim 13 or claim 14.